Nitro-starch explosive.



UNITE STAIEEPAXTENT OFFICE.

JESSE B. BRoNs'rEIN'ANn CHARLES E. WALLE 0P ALLEN'roWN, PENNSYLVANIA, ASSIGNORS T0 INDEPENDENT NON-FREEZING POWDER COMPANY, OF NEWARK, NEW JERS Y. A coRPoRATIoN oP NEW JERsEY.

NITRO-STARCH ExPLosIvE.

1.1882316. Ho Drawing.

To all whom it may concern:

Be it known that we. JESSE I3. BRoxs'rEIx and CHARLES E. "WALLER, citizens of the United f5tates, and residents of Allentown,

been made containing nitro-starch as the explosive base (and 111 using the term "nitrostarch explosives we refer to explosives such as employ mtro-starch as an explosive base and are used for blasting purposes),

nitrate of soda as the oxygen carrier and suitable quantities of an anti-acid such as calcium carbonate and of a waterproofing material such as paraflin oil. These powders have been graded to suit conditions encountered inpractice. by varying the percentage of nitro-starch and nitrate of soda. This type of explosive has been quite widely used and found satisfactory for many purposes.

Ordinarily in order to get the best results' from the explosive, it is desirable that the shattering force or brisance and the propellent force of the explosive be fairly well balanced; For use, however, in underground operations, where the rock is extremely hard, it is necessary to have an explosive. the energy of which is chiefly developed as shattering force. or brisance, and

.the object of the present invention is to pro vide a Intro-starch explosive, cheap and efficient, but with greater relative shattering than the nitro-starch powders as heretofore made.

We have discovered that by substituting, within certain limits, barium nitrate for a portion of the sodium nitrate ordinarily employed as the oxygen carrier in Intro-starch powders, a certain proportion-of the propellent force of the explosive can be converted into shattering force or 'brisance. In

Specification of Letters Patent.

" aspect I Patented June 20, 1916.

Application filed July 6, 1914. Serial l lo. 849,259.

fact, experiment has shown that the shattering force of nitro-starch explosives may be increased about twenty per cent. by substituting about thirty per cent. of barium nit-rate for a like proportion of sodium nitrate ordinarily employed as the oxygen carrier.

The substitution of barium nitrate for a portion of the sodium nitrate oxygen carrier 'has these advantages. In the first place, it

has a smaller oxygen excess than sodium nitrate andf for this reason gives an in-' creased ter'np erature of explosion in those explosives which would otherwise contain a considerable excess of free oxygen; secondly, it appears to carry its oxygen in a more readily available form; thirdly, the specific gravity of barium nitrate is greater than that of sodium nitrate. thereby resulting in a denser charge which results in a greater shattering .force by reason of the fact that the smaller the charge chamber for a given amount of explosiveenergy, the more violent will be the action of the explo sive on the surrounding matter. By reason of the smaller oxygen excess referred to,

the employment of barium nitrate in the manner described is particularly useful in powders of low grade, where the relatively smaller amounts of the explosive base lead to oxygen excess, and also in powders where oxygen excess is due to any other cause, as for example where a portion of the nitrostarch has been replaced by other agents,

such for example as a mixture of ammonium nitrate andtrinitrotoluene as described in our application 1913, Serial No. 783,601. But in'the broader of our invention, we do not wish to be confined to the employment of barium nitrate with any specific nitro-starch powder, as said material can be usefully employed as a substitute for a portion of the oxygen carrier in. nitro-starch explosives generally.

e have found that the/addition of barium nitrate to nitro-starch explosives increases for patent filed August 7,

the susceptibility of the explosive to the effect of the detonating cap, and experi ent has indicated that the facilitywith W ich the detonating wave passes through the pow reduces the tendency to absorb moisture.

There-are of course limits to the propertions' of barium nitrate whichcan be successfully employed and we believe thatsaid mgredient could not be successfully employedinexcess of forty per cent. (40%) by weight of the entire explosive. As one example of a nitro-starch powder employing barium nitrate in the .mannerjhereinbes fore described, we give the following formula Nitro-sta-rch 40. 0% Sodium nitrate 37. 7 Barium nitrate 20. 0% Calcium carbonate 1. 5% Paraffin oil 8% In some instances it is desirable to increase the shattering force or brisance of the ex plosive beyond that possessed by such a .m-ixture as is set forth in the formula just given, and we have found'that if in addition to the other ingredients including barium nitrate, a proportion ,of sulfur be added to the mixtiu'e, we can 'obtain the-increased shattering force desiredp We believe that this result-is dueto the reaction which occurs on explosion between the barium'nitrate and the sulfur, which results in amarked and unusual increase of temperature, a result which is not approached 0r attained when either the barium nitrate or the sulfur is alone in the explosive. For the purpose stated the sulfur should not be used in quantities substantially in excess of eight per cent. (S%)-'by weight of the entire'mixture-.

As an illustration of a nitro-starcli powder cmploying'bar um nitrate and sulfur in the manner described, we give the following formula:

P araiiin oil .8% Sulfur 3. 0% 100.0%'

' Asan illustration of a nitro-starch powder including ammonium nitrate-trmitrotoluene mixture and also employing our present in- Ye are aware that it has heretofore been proposed to make use of barium nitrate as an oxygen carrier in certain types of 'ex-- plosives, but we are unaware. that this has ever been done in connection with powders of the class with which we'are working, or that it has ever been. done in connection with nitro-sta-rch powders of the detonating type, and we believe that we are the first 1 to suggest the employment of barium nitrate as a substitute for a portion of the-sodium nitrate oxygen carrier ordinarily employed with nitro-starch powders. Further we be-' .lieve that the advantages incident. to the use of barium nitrate hereinabove set forth have not heretofore been developed and are such as would not have been anticipated. by those skilled in the art. v

As'this application possesses matter in common with an application filed by us August 7, 1913, Serial No. 783,601 is to be treated as a continuation of said prior. application as far .as the common subject-matter is concerned;

-1. A detonating explosive containing nilp (40%) by weight of the entireeiq ilosive.

2., A detonating explosive containing nitrostarch, sodium nitrate, and barium nitrate; the barium nitrate being not less than twenty per cent. (20%) nor more than forty per cent. (40%).by weight of the entire explosive.

3. A detonating explosive contai ing nitrostar ch,' sodium nitrate, barium nitrate and sulfur. I 4. A detonating explosive containing nitro-star'ch, sodium iitrate, bariu nitrate not exceeding fortyper cent by weight of the entire mixture, and sulfur not substantially exceeding eight per cent. (8%) by weight of the entire mixture.

In testimony whereof, we have signed our] I 120 names to this specification, two subscribing witnesses.

JESSE B. BRONSTE N. CHARLES E. \VALLE in'the presence of Witnesses:

M. ELEANOR RoBERT's, Jos. H. KLEIN. 

